Numerical Investigation of Aerodynamics of a Wing with Spanwise-Varying Flap Deflection.

This study presents a numerical investigation of the aerodynamic effects of flap deflection, which varies along the span of the wing, with particular emphasis on lift distribution and wake formation of the flow. The objective of this study is to understand non-uniform flap deflection, which can be used as a passive flow control strategy in order to improve the efficiency of the wing. Two spanwise flap deflection profiles are considered, linear and cosine, in which deflection is maximum at the wing root and decreases towards the wing tip following the respective functional distribution. These include incompressible and compressible flow regimes to measure the overall impact of flap scheduling and compressibility on overall aerodynamic performance. Aside from analyzing global aerodynamic forces (lift and drag), the study also estimates pressure recovery and pressure uniformity to better characterize flow quality and the mixing of the flow downstream. The flow physics are analyzed from the surface- and field-based visualizations with flow path characteristics such as static pressure, Mach number, Q-criterion and streamlines, which provide the ability to clearly see separation directions, vortex cores and wake thickening features. The key findings of the study provide deep insights about pressure distribution and circulation, which significantly influences aerodynamic performance of the wing. These insights will help in designing a flexible wing with variable flap deflection. Such configurations have strong potential applications in the field of UAVs and commercial aircraft.